Most foods are carbohydrates, which are converted to sugar by the digestive process. Cells absorb this sugar in order to support life. Insulin, a hormone produced by the pancreas, is key to the absorption of sugar by the cells. Without this hormone being present, the cells will not absorb the sugar, and will die. A diabetic who is dependent on insulin injections typically does not produce his or her own insulin, and therefore needs to take insulin shots to survive.
The medical community uses a scale of 0 to 540 mg/dl to represent the amount of sugar in the blood. Low blood sugar is considered to be 0–70. Normal blood sugar is considered 70–126. High blood sugar is in the range 126–200. Very high blood sugar is over 200.
Below 70 is a condition known as very low blood sugar (hypoglycemia). This is the level at which brain damage and death can occur if immediate action is not taken to correct the situation. At 200 and above is a condition known as very high blood sugar (hyperglycemia). As the sugar level approaches 540, brain damage and death can occur if immediate corrective action is not taken. At both ends of the spectrum, very high and very low, a diabetic will go into a coma.
To correct a very low blood sugar condition, it is necessary to get sugar into the blood immediately, by ingesting sugar or its equivalent: for example a high-sugar fruit juice such as orange juice. In an emergency, a glucose injection can be given. Typically, blood sugar will rise within minutes.
To correct a very high sugar condition, only insulin can help. Even quick-acting insulin still takes hours to reduce a high sugar condition. It is, therefore, easier to deal with low blood sugar than high blood sugar.
Normal blood sugar levels are between 72 and 126, with a buffer up to 200. Between 200 and over 500 is the territory of the diabetic sufferer. Long-term sugar levels in this range will cause blindness, kidney failure and nerve damage, as well as increasing the risk of heart attacks fourfold. Allowing sugar to go over 200 is dangerous because at that point excess sugar will be flushed from the blood, and out through the kidneys with urine. This level of 200 is known in medical terms as the “renal threshold” with the word “renal” meaning “kidney”. In other words the sugar spills from the blood, through the kidney and into the bladder.
The 108–144 range, rather than 72–126, provides a cushion to protect from a dangerous low blood sugar condition that can occur below 72. While a diabetic would prefer to stay at 126 or under, practice will show that this is hard to achieve safely. Any damage between 126 and 144 is very small, and is preferable to sliding under 72. So a diabetic may aim for 100 or 110 to 126, but is not over-concerned at a reading between 126 and 144.
As sugar edges toward the high end, a diabetic gets sleepy and lethargic. Just a little high, and the subject feels quite normal.
Those who do not know that they are diabetic have no way of seeing their blood sugar, so they feel quite well with their sugar in the 215–250 ranges. However, with sugar at that level for several years, serious damage to the body can occur.
A diabetic can lead a healthy lifestyle, and still succumb to the complications of the disease. There are four major targets of this disease, that can be attributed directly to excess blood sugar:
Arteries and Heart
As excess sugar accumulates in the bloodstream it causes the walls of the arteries to harden. This hardening will eventually contribute to clogging of arteries, leading to an increased chance of heart attack. Diabetics with poorly controlled blood sugar levels have a four times greater risk of heart attack than non-diabetics. The risk of stroke is also significantly increased.
As excess sugar accumulates in the bloodstream it causes the walls of the arteries to harden. This hardening will eventually contribute to clogging of arteries, leading to an increased chance of heart attack. Diabetics with poorly controlled blood sugar levels have a four times greater risk of heart attack than non-diabetics. The risk of stroke is also significantly increased.
Kidneys
The level 200 on the scale is the level at which the body tries to rid itself of the excess sugar, by dumping it into the urine; this is the “renal threshold”. In fact, sugar in the urine is one way of diagnosing diabetes since a person without diabetes will not show sugar in the urine. Thirst and frequent urination are symptoms of diabetes because the body is trying very hard to increase the intake of fluids, which help dispose of this excess, unwanted, dangerous sugar. The body either has increased sugar in the blood, which can lead to heart failure, or releases the sugar into the urine, which can lead to kidney failure. The kidneys, however take a lot longer to fail than does the heart, so the body chooses the route that will give it the longest time to survive.
Even at 90% failure the kidneys will still operate, and the diabetic may feel quite normal. However, every 1% drop in kidney function thereafter will have the impact of losing 10% of remaining kidney function, and serious medical consequences result. Within several months of the kidney function dropping below 10%, kidney failure will occur.
Eyes
The eyes are filled with a dense fluid. When there is excess sugar in the system, this fluid becomes denser, requiring more fluid to regain its optimum density. This extra fluid is forced into a space that has very few expansion possibilities, and results in putting pressure on the retina, leading to the condition known as glaucoma. At the same time, the arteries supplying blood to the eyes also become hardened, resulting in additional pressure at the back of the eye. Caught between these two pressures, the eyes suffer a variety of complications that damage the retina, and can eventually lead to total blindness.
Other retinal disease can also be brought on as a by-product of uncontrolled diabetes.
Feet
A lot of diabetics suffer from pain in the legs and feet, eventually losing feeling in the soles of their feet. A by-product of spilled sugar is an insoluble substance called sorbitol, which gets inside the myelin sheath (insulation). After accumulating in the myelin sheath for some time, it eventually ruptures it, causing the exposed nerve to stop functioning. The resultant loss of feeling makes walking very difficult, like walking with frozen feet, and also makes it very difficult to feel any pain or discomfort.
Another complicating factor of continuing high blood sugar is poor healing. High sugar concentration in the blood leads to poor circulation, which interferes with the natural healing process. This is one of the reasons why diabetics with poor control of their sugar have ulcers that don't heal.
Food and Blood Sugar
There are two types of diabetes, called Type 1 and Type 2. The difference between them is, that most Type 2 diabetics develop their condition in adulthood, and can control it through a combination of diet, exercise, and weight control, whereas most Type 1 diabetics often develop their condition as children, and must take insulin to stay alive.
A person who does not have diabetes controls his sugar automatically and unconsciously, without being aware that it is even happening. Sugar stays in the 72 to 126 range, and any excess sugar is quickly removed, and stored as fat, for future use. The key to this automatic regulation is insulin: a hormone produced by the pancreas.
Type I diabetics lose the ability to make this hormone, often because of an autoimmune response in which antibodies destroy the cells that make insulin. They have to rely on insulin injections to live. The amount of insulin required is based on several factors, the most important one being the amount of food that is eaten. As a result, they have to be very careful about their food intake, in order to control their blood sugar.
Type 2 diabetics lose, to varying degrees, the ability to absorb insulin into their cells, where it could enable the cells to metabolize sugar. It is rendered more severe by excess weight, and is controlled by diet, exercise, pills, and sometimes by extra insulin.
Different foods have different absorption rates. For example, a half a glass of orange juice may enter the blood within five minutes. In fact, because of its speed, it is recommended as ‘quick sugar’ when blood sugar falls below 72. If this juice is consumed in the form of an orange, it takes much longer for it to become blood sugar. Eating unprocessed whole grain foods, such as regular oatmeal, takes hours before it all is converted to sugar.
At one end of the spectrum are ‘quick sugars’ like packaged cereals, and at the other end, are ‘slow sugars’ such as pasta or whole grain bread. Quick sugars enter the blood in about an hour, although the presence of fiber and fat can slow this down. Slow sugars take about an hour to start entering the blood stream, and this effect can spread over about three hours, or even longer. The rate at which various carbohydrate foods enter the blood as sugar is called the glycemic index. Categories of sugars are below:
Fast-absorbing: (and demanding fast-acting insulin): high glycaemic indexHighly processed grains and potatoes including packaged cerealsand instant rice and potatoes.Less processed grains, like whole wheat bread, instant oatmeal,and non-instant riceMaltose, glucoseCarrots, parsnips and cornBanana, raisins, apricots, papaya and mangoCorn chips snacks and low-fat ice-creamModerate glycaemic indexPasta, heavy breads, all-bran cerealOranges and orange juiceMost peas and beansLactose, sucroseCandy bars, potato chipsFairly low glycaemic indexSlow cooking oatmeal, barley, heavy rye breadsApples, pears, grapes, peachesLess processed peas and beansMilk, yogurt, fat ice creamLow glycaemic indexCherries, plums, grapefruitFructoseFatty beans and nuts, such as soy beans and peanuts
So, in order to keep his sugar in the 72–126, or 100–144 range, the diabetic not only has to count his sugar, but must also be familiar with the absorption rates of different foods. For instance, if the sugar reading is 108 and the diabetic drinks an 8 oz. glass of orange juice, his sugar will go up to about 250 within a few minutes. It might then take 2–3 hours for it to go back to 144. Those hours in the ‘spilled sugar’ condition (over 200) result in diabetic complications in the future, and the time spent between 144 and 198, while not spilling sugar, still adversely affects health. If a cup of whole grain pasta is chosen instead, it would put sugar into the blood at about the rate that insulin absorbs it. As a result, the sugar is unlikely to go above 200.
The foods that convert to sugar are starches and fruits. Proteins and fats have no direct impact on blood sugar, but they do affect it indirectly.
Without going into all of the parameters in great detail, it is clear that diabetics need to watch all elements of a diet in order to achieve normal sugar levels. There is a need for a simple method to juggle the various food parameters in order to achieve healthy blood sugar levels.
Measuring Sugar
There are two basic measurements that tell how much sugar is in the blood. One measurement is the current amount of sugar in the blood.
The meters that are purchased at drug stores come in two varieties: those that measure sugar on the scale discussed above (0–540+) and those that come with a different scale (0–30+), or 1/18th the 0–540 scale. The diagram below shows how these two scales correspond:

The 0–540 scale is used in the United States, and the 0–30 scale in Canada. The rest of the world uses one or the other.
It is vital that the meter be very accurate. Studies have shown, that relatively small differences in a diabetic's long-term sugar level have a significant impact on his health. 108–126 is good, while 144–162 is somewhat harmful, and over that is more seriously damaging.
The long-term blood sugar level has to be measured in a laboratory and is known as HbA1C or glycosolated hemoglobin. It is presented on a scale of 4.5% to as high as 20%, in extremely ill persons. HbA1C is one of three types of oxygen-carrying hemoglobin found in the body, and when it contacts glucose molecules in the blood, some of them stick to it. The more glucose there is in the blood, the more that sticks to the HbA1C, and this can be measured to give a percentage saturation, that translates into an average blood sugar. Because HbA1C cells live about three months, this shows the level at which the blood sugar has been, on the average, over a three month period.

It is the three month measure that indicates how well a diabetic is controlling sugar. It is very possible to get a single high or low reading. An HbA1C reading of 6–7% indicates that a good level of control has been achieved. The current optimum HbA1C recommendation is 6.5%.
Some diabetic subjects have tried to balance carbohydrates with insulin by carbohydrate counting. This involves counting carbohydrate grams in food based on the large amount of self-management data currently available. Carbohydrate choice counting is typically based on the portion of a 15 g equivalent of carbohydrate on which the exchange system is based. The system categorizes foods by lists that have similar macronutrient and energy values. However these systems are not individualized by considering the particular rate of carbohydrate release in a subject or the rate of sugar removal by insulin administered to the subject. There remains a need for a more precise and simple way to balance diet and insulin intake in a diabetic subject.